Known alarms, whether they be those which equip timepieces furnishing basic time information or those which equip personal searching devices are designed to signal a specific event such as an alarm time or a radio-telephone call by furnishing a selected sound within a range or according to a specific tonality.
This type of alarm exhibits the basic drawback of being perceptible in the surroundings of the user which, in the alarm function, does not enable distinguishing the user from other persons. Furthermore, in its application to a searching device for persons (pager), this type of acoustic alarm informs all persons present, for example during a work conference, at the same time as the user of the call received by such user.
Thus, it is understood that this type of acoustic alarm exhibits a drawback of not being discreet and that in being perceptible to persons other than the user, it does not enable easy differentiation of one of the users in a group of other persons.
To overcome this, silent, non-acoustic alarms have been proposed which include motor means driving a mass designed in a manner such that during its displacement such mass furnishes a vibratory effect which can be transmitted to the user. The vibration perceptible by such user thus warns him and him alone of the alarm time or the call received.
A non-acoustic alarm of this type is described in the patent application EP 0 349 230. Such alarm includes a piezo-electric motor which drives in rotation an eccentric mass movably mounted on a spindle.
Because of the coaxial configuration of this arrangement, the latter exhibits a relatively substantial space requirement in thickness, so that it necessitates a specific layout in order to be mounted in a timepiece, indeed a complete redesign of such timepiece.
Furthermore, such arrangement necessitates providing a piezo-electric motor the manufacture of which calls on relatively complex techniques. Additionally, it is known that piezo-electric motors operate on the friction principle and that they undergo substantial wear and thus have a limited life duration.
Finally, this arrangement requires an extremely precise assembly of the mass on its spindle which it stresses highly because of the vibratory motion.
The present invention thus has as purpose to provide a non-acoustic alarm of simple conception capable of equipping information supplying devices such as a timepiece without necessitating substantial modification of the structure thereof and capable of being formed at the lowest possible cost by high speed automatic operations.